How Does an Onion Affect Tear Ducts?
Irritating Compounds When an onion is sliced, it very quickly releases strong, sulfur-based compounds into the air. When these compounds waft up to the eyes, they interact with the moisture on the eyeballs. The moisture causes the sulfur compounds to produce mild sulfuric acid, which burns and irritates the eyes. Triggering Tears The nerves in the eyes are extremely sensitive and pick up on the sulfuric acid almost immediately. A message about the invader is transmitted to the brain. The brain, in turn, tells the tear ducts to begin flushing out the irritant with moisture. This triggers the tears that are most often associated with slicing onions. The Science Behind the Reaction Tears are the body’s first natural defense mechanism for the eyes. In telling the tear ducts to release moisture, the brain is attempting to flush out the irritating substance before it causes permanent damage to sight. Some ways to avoid tears while slicing onions include wearing glasses or other protective go
